Race Definition and 226 Threads

  1. J

    Trying to tie two runners of different speeds over a race

    Attempt is attached, thanks for the help :)
  2. martonhorvath

    Optimizing energy expenditure over a race course in cycling

    $$W = W_{gravity} + W_{friction} + W_{air}$$ Dividing by s: $$F_{total} = mg(sin(\alpha)+\mu cos(\alpha))+0.5×C_{d}A\rho×(v+v_{wind}×sin(\beta))^2$$ Then expressing v for both sections separately: headwind: $$0.5×C_{d}A\rho×v^2+v_{wind}×sin(\beta)×C_{d}A\rho×v+mg(sin(\alpha)+\mu...
  3. C

    A Runners in a race, probability paradox

    There are a number n of runners in a race. We know their expected times from start to finish μ(i) and the corresponding standard deviations σ(i). The probability of runner 0 to finish first is given by this integral: It's from here: https://www.untruth.org/~josh/math/normal-min.pdf The 0 is...
  4. ChanYeol

    I am making an alien race and need help with their biology

    I would like a reason why their blood is Cooper/ Rose gold color. They evolve from a dinosaur bird like creature but in their current timeline they are human looking. One of their most strange characteristic is they got cooper looking veins and their blood is rose-gold color. Which gave the...
  5. S

    What Are the Key Perspectives on Life?

    From my point of view: 1) survival 2) do something good to satisfy your inner soul and for others. 3) help to continue the race of human being 4) and die What others think about life?
  6. dom_quixote

    B Rabbit and Turtle Race: A Mathematical Analysis of Infinity and Probability

    A Mathematical Fable: Rabbit versus Turtle Race a) Rabbit and turtle combined a race along a road of infinite length. b) As time progresses to infinity, the distance between the rabbit and the turtle tends to infinity. c) As time progresses, both animals approach infinity. d)The closer time...
  7. knapklara

    Simple kinematics question -- Riding a bicycle race in two different gears

    I calculated average velocity but obviously it helps nothing with this problem. I hope to get me going with these exercises once I break the ice. Thank you in advance!
  8. rudransh verma

    Comparing 1000m Race Velocities: Runner 1 vs Runner 2

    First I calculated the avg velocity with 1000m for both runners. It came 6.76m/s and 6.75m/s. It suggests that the velocities are same. This means yes that the L2 track is slightly longer than L1. Then why is it asking this question (…that runner 1 is faster)? Both are at equal speeds. I don’t...
  9. anorlunda

    Could stopwatch errors change race results, and physics experiments?

    Ay ay ay. Here's yet another worry to give you headaches.
  10. cle102

    Uniform Circular Motion: banked race track circular path

    Basically, I need help to continue on this question. This is what I have now: Angle of the race track (angle of the grey part): tan(18/(169-108)) = 0.30396 Not sure how to continue?? What am I supposed to do and find next? Thank you in advance! :smile::blushing::oldbiggrin:
  11. MrMoe

    Bearing race diameter inequality question

    Hello all this is my first post. I am not an engineer, but I wish I was. I have been enjoying watching Dan Gelbart!s YouTube Chanel. His air bearing has me wondering about the relationship and apparent conflict inside ball bearings. How does the ball travel around the shorter distance...
  12. arkantos

    I Who Will Win the Race at the Event Horizon?

    Hi guys. Imagine that in the exact instant when a massive particle A crosses the event horizon of a black hole, a Photon does the same,so that they have a race toward the singularity. Who will win the race? Will they have still different velocities?
  13. T

    B Who will win this running race?

    Who will win this running race? How many seconds are their scores?
  14. E

    What is the optimal power variation for a cyclist on a varied race course?

    I just thought up a little problem and wondered whether anyone could advise as to how to go about it! On a flat course, suppose a cyclist might be able to maintain 300W for around an hour. This gives a total allowed energy expenditure of ##1080t \text{ kJ}##, where ##t## is measured in hours...
  15. CanFan

    B What sort of can would roll the fastest?

    Hello, I'm new here so apologies if this is in the wrong place! I was wondering, hypothetically, what sort of canned food would roll the fastest (assuming the ramp remained constant and the can couldn't be altered)? I've been looking this up and I know a solid can would roll faster than an...
  16. DracoMalfoy

    Motion in One Dimension: The Tortoise and The Hare Race

    Homework Statement A turtle and a rabbit engage in a footrace over a distance of 4.00km. The rabbit runs 0.500km and then stops for a 90min nap. Upon awakening, he remembers the race and runs twice as fast. Finishing the course in a total time of 1.75h, the rabbit wins the race. A) Calculate...
  17. N

    B Planet Nine race, how is it going?

    Pardon this possibly information-free post... Since Mike Brown published his papers on the possibility of ~10 Mearth mass body beyond ~200 AU, and it was discussed a lot, I imagine now there is sort of a quiet race among astronomers in TNO field to find this thing. IIUC, Mike has his own team...
  18. M

    Electric racing -- Custom 4WD Electric Race Car Advice Please

    [Mentor's note: two threads on the same topic have been merged] I live here in Stephenville, TX and currently going to Tarleton for Civil engineering. A bit rusty and new to electrical components. But anyways, here in town lawnmower racing is kind of a big event. Many of us have 600cc crotch...
  19. P

    Maintaining interest in the new 'private' space race

    It's said that expectations drive the economy. So, how do you maintain interest in something that has no immediate bearing/benefit/utility of a population? I would think the answer to that question is to manifest a 'goal', in this case being an interplanetary species or even just building a...
  20. B

    Optimizing Rally Race Time with Maximum Acceleration and Deceleration

    Homework Statement In a rally race a pilot must travel in a minimum time ##t## a road long ##d=1 km## (the road is straight). Before he starts he is still and he must end still (so the speed at start and end is zero). The maximum acceleration is ##a_1=2,5 ms^{-2}## and the maximum deceleration...
  21. I

    Automotive Car downforce: accelerating air under the car vs blocking

    As most of you know real racecars have flat bottoms, rear diffusers and in the front well... a variety. So to keep this simple. I am building a car with a flat bottom and rear diffuser, car raked at 4 deg, diffuser at 14 (all details will be adjusted based on learned info) and nothing on top or...
  22. mastermechanic

    Automotive Why race cars have stationary spoilers?

    I frequently hear something like "...this car have stationary spoiler like race cars" bla bla. Why are stationary spoilers used in motorsports? Active spoilers are very useful for breaking and accelerating. I want to know the reason behind it. Thanks.
  23. Cheesycheese213

    Mousetrap race car is not working

    Hello, so for school I'm building a mousetrap with my group for a project, but our car isn't moving. We filmed it snapping, and it doesn't seem like it is because of friction, since the axle spins pretty well. We thought that it was because the thing that holds the axle bends, but after fixing...
  24. S

    Relative velocity during a race?

    Hello, could someone please check my answer for this problem. All of my work and equations are clearly presented in the picture attached below. (If my answer is wrong, please give me pointers on how I could obtain the correct solution). Thanks! Problem 5: On their way to play soccer in...
  25. 1oldman2

    News Is the Nuclear Arms Race Making a Comeback?

    As if we don't have enough to worry about already, I hate to think where this is leading us. http://www.cnn.com/2016/12/22/politics/donald-trump-strengthen-expand-nuclear-capability/index.html (CNN)President-elect Donald Trump signaled Thursday that he will look to "strengthen and expand" the...
  26. FallenApple

    I Cylinder Beats Sphere in Race (weird case)?

    Ok so we all know that when rolling down a fixed incline under gravity, a sphere will beat a cylinder in a race due to the fact that it has less rotational inertia. However, in the following set up, the cylinder beats the sphere. Say the cylinder and sphere are side by side on a horizontal...
  27. C

    Slipping vs No Slipping Ball Race

    The setup is a flat friction surface where the ball rolls without slipping. Next, in one case it goes up a friction incline, and in the other a frictionless incline. Which ball leaves the incline faster? Both are given the same initial push. At the bottom of the incline both balls have the same...
  28. A

    MHB Algebra help - a race around a regular polygon

    Bert and Ernie are running around a regular polygon with x sides, all of length 12m. They start from the same point and run in opposite directions. If Bert is twice as fast as Ernie, how far will Ernie have traveled when they meet?
  29. M

    MHB How to compare race times from one race to another race?

    My son competed in a race over the weekend, and we are trying to figure out how he did overall compared to kids in similar races around the country. I am not very good in math, but I want to help him. Can this/ should this be done as a percentile? How? Other thoughts about how to approach...
  30. R

    Automotive Standing mile race car twin engine heavy front end?

    got a twin ls1 standing mile car project I've been toying with for a while.My question is the engines have beeen fit in the engine bay with the rear motor having minimal setback to allow room for the front engine,the total weight for both engines is 760 lbs,half of that weight is ahead of the...
  31. O

    Coriolis Force on a Race Car at 45 Degrees North

    Homework Statement Find the magnitude and direction of the Coriolis force on a racing car of mass 10 metric tons traveling due south at a speed of 400km/hr at a lattitude of 45 degrees north. Homework Equations F_{cor}=-2m\omega\times v The Attempt at a Solution \omega=2\pi/(24*3600 \quad...
  32. physicaled

    Can a Tiger Outrun a Lion in a 100 Meter Dash?

    Homework Statement In a 100 m race between a lion and a tiger, the lion starts from rest and accelerates at a rate of 2 m/s2 for 5 seconds, then maintains a constant velocity for the rest of the race. The tiger starts from rest and accelerates at a rate 3 m/s2 for 4 seconds, then maintains a...
  33. M

    Automotive Electric race car cooling system

    hello everybody! As an undergraduated student of engineering I have to design a elecric car radiator from the beginning! The truth is that am a little confused.. I started my calculations by estimate the rate of heat transferred by the drivetrain and finding the maximum delta T needed.. any idea...
  34. Z

    Race Car Scenario: Who will win?

    Homework Statement Our professor has tasked us to come up with a thought experiment to test the following scenario: "Two vehicles are going to race a fixed distance, both starting from rest. One vehicle has a greater maximum acceleration than the other, but a lower maximum speed. If both...
  35. goonking

    Two-Wheeled Car Race: Friction - Help or Hindrance?

    Imagine a car race about to take place. A car is starting at rest and when the timer goes off, the driver steps on the gas. The car starts off so fast, that its front wheels rise upwards so that all the weight of the car is held up by the 2 rear wheels. The car travels this way for a few...
  36. Noisy Rhysling

    What do you consider to be the most interesting alien race?

    I have a fondness for the Moties from The Mote in God's Eye and it's sequel, The Griping Hand. They are a hierarchical society with a biological necessity to reproduce or die. This leads to incredible population pressure and resulting societal collapse. Being "trapped" in one solar system they...
  37. J

    Motion Questions -- Acceleration of a race car....

    I have been struggling to understand how to do this question so some guidance would be great. A racing car of mass 941kg accelerates from 28km/h to 102km/h over a distance of 297m. Frictional forces and wind resistance can be assumed to be 1160N. Determine the following: a) The average...
  38. Greg Bernhardt

    What 20k race cars on a track looks like

    This is a simulation and some of the crashes are really epic!
  39. RooksAndBooks

    News Graham Drops out of the 2016 Presidential Race

    Lindsey Graham is a Senator who ran for president. Recently, however, he has decided to drop out of the race. The problem I see with this video is that he doesn't explain why he is leaving the race. He only says that he's leaving the race and talks about the military. I personally think that...
  40. H

    Exploring 4D Worlds: A Visual Journey Through Extra Dimensions

    I've been wondering what spaces with an extra physical dimension would look like. That is, instead of our 3+1D space it would be a 4+1D space. In general, it can't be done. There is too much information for a human brain to handle. But some special cases can work. The main one I thought of...
  41. H

    Calculating Torque and Friction for a 4-Wheel Drive Car | Homework Solution

    1. Homework Statement A 4-wheel drive car of mass M = 2100 kg accelerates from rest to 100 km/h in 3.40 seconds, and we will assume that the acceleration is constant. In the following, ignore resistance from the air and the rolling friction of the wheels against the surface. The wheels are...
  42. O

    Calculating Race Time and Length with Different Speeds and Rest Periods

    Homework Statement A tortoise can run with a speed of 10.0 cm/s, and a hare can run exactly 10 times as fast. In a race, they both start at the same time, but the hare stops to rest for 3.00 min. The tortoise wins by 10 cm. (a) How long does the race take? (b) What is the length of the race...
  43. B

    News Breaking Down the 2016 POTUS Race Contenders & Issues

    Who are the top contenders for 2016 POTUS and what are the major issues (and each contenders' stance on them)? Discuss, discuss, discuss... All I know is that Hillary and Trump look like the most popular at the moment.
  44. D

    How far will two people travel in a race?

    Homework Statement John and Fred are racing. Fred, being faster, gives john a 20 s head start. John runs at 12 km/hr (10/3 m per second) and Fred at 16 km/hr (40/9 m per second) How long after John starts will Fred catch him? How far from the start do the two meet? Homework Equations d =...
  45. CleverBigIdeas

    Automotive Race Car Safety: Protecting the Driver's Waist Down Area

    I have been thinking about racecar safety, specifically protecting the driver's waist down area. I was thinking of a transmission tunnel, firewall area, and floor board (just by pedals) Here's The Idea: What if I used a Carbon Fibre/ Kevlar weave to be flexable into the position you want then...
  46. R

    Why is the Moon going above Jupiter in the sky?

    I went for a walk in a big park for 3 days. On first day I saw moon above Mars relatively in sky . Mars was looking like a pointy star being red in colour. The next day I saw Mars relatively above moon. The third day moon above Mars again and they rising high and high. Are they both having a...
  47. N

    How much of a head start does B need to win the race?

    Hey all. Simple problem here. 2 people are running at 2 different speeds in a race 50m long (A at 5 m/s B at 3 m/s), A is clearly going to win, How much of a head start would B need to win? (This isn't a homework problem I'm just wondering how long I have to wait for my movie to buffer before I...
  48. K

    Left/Right Communication with Alien Race by Richard Feynman

    Hi all, I was thinking about the problem and can someone verify my solution : 1) Set up a Magnetic field going from down to up, i.e north pole is at the bottom. 2) Use the triboelectric series to charge some small particle positive (hair or glass with teflon) 3) Throw that particle in forward...
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